InfoScale™ 9.0 Storage and Availability Management for DB2 Databases - AIX, Linux
- Section I. Storage Foundation High Availability (SFHA) management solutions for DB2 databases
- Overview of Storage Foundation for Databases
- About Veritas File System
- Overview of Storage Foundation for Databases
- Section II. Deploying DB2 with InfoScale products
- Deployment options for DB2 in a Storage Foundation environment
- Deploying DB2 with Storage Foundation
- Deploying DB2 in an off-host configuration with Storage Foundation
- Deploying DB2 with High Availability
- Deployment options for DB2 in a Storage Foundation environment
- Section III. Configuring Storage Foundation for Database (SFDB) tools
- Configuring and managing the Storage Foundation for Databases repository database
- Configuring the Storage Foundation for Databases (SFDB) tools repository
- Configuring authentication for Storage Foundation for Databases (SFDB) tools
- Configuring and managing the Storage Foundation for Databases repository database
- Section IV. Improving DB2 database performance
- About database accelerators
- Improving database performance with Quick I/O
- About Quick I/O
- Improving DB2 database performance with Veritas Concurrent I/O
- Section V. Using point-in-time copies
- Understanding point-in-time copy methods
- Volume-level snapshots
- Storage Checkpoints
- Considerations for DB2 point-in-time copies
- Administering third-mirror break-off snapshots
- Administering Storage Checkpoints
- Database Storage Checkpoints for recovery
- Backing up and restoring with Netbackup in an SFHA environment
- Understanding point-in-time copy methods
- Section VI. Optimizing storage costs for DB2
- Section VII. Storage Foundation for Databases administrative reference
- Storage Foundation for Databases command reference
- Tuning for Storage Foundation for Databases
- Troubleshooting SFDB tools
About the Veritas File System intent log
Most file systems rely on full structural verification by the fsck utility as the only means to recover from a system failure. For large disk configurations, this involves a time-consuming process of checking the entire structure, verifying that the file system is intact, and correcting any inconsistencies. VxFS provides fast recovery with the VxFS intent log and VxFS intent log resizing features.
VxFS reduces system failure recovery times by tracking file system activity in the VxFS intent log. This feature records pending changes to the file system structure in a circular intent log. The intent log recovery feature is not readily apparent to users or a system administrator except during a system failure. By default, VxFS file systems log file transactions before they are committed to disk, reducing time spent recovering file systems after the system is halted unexpectedly.
During system failure recovery, the VxFS fsck utility performs an intent log replay, which scans the intent log and nullifies or completes file system operations that were active when the system failed. The file system can then be mounted without requiring a full structural check of the entire file system. Replaying the intent log might not completely recover the damaged file system structure if there was a disk hardware failure; hardware problems might require a complete system check using the fsck utility provided with VxFS.
The mount command automatically runs the VxFS fsck command to perform an intent log replay if the mount command detects a dirty log in the file system. This functionality is only supported on a file system mounted on a Veritas Volume Manager (VxVM) volume, and is supported on cluster file systems.
See the fsck_vxfs
(1M) manual page and mount_vxfs
(1M) manual page.
The VxFS intent log is allocated when the file system is first created. The size of the intent log is based on the size of the file system - the larger the file system, the larger the intent log. You can resize the intent log at a later time by using the fsadm commnad.
See the fsadm_vxfs
(1M) manual page.
The maximum default intent log size for disk layout Version 7 or later is 256 megabytes.
Note:
Inappropriate sizing of the intent log can have a negative impact on system performance.